Headlight lens



F. C. ASHE.

HEADLIGHT LENS.

APPLICATION FILED NOV. 1. 1919.

ILALSQQQWZ 2 SHEETS-SHEET l.

i ll Patented Oct. 17, 11922 F. C ASHE.

I HEADLIGHT LENS.

APPLICATION FILED NOV. I 1919.

l qsg wm, Patented 001;. 17, 1922.

2 SHEETS SHEET 2.

. Pittsburgh, county of Allegheny,

Patented @et. 17, 51922.

UNHTEH) stares entrant @FFHQE.

FR 0. ASHE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO PITTSBURGH LAMP, BRASS @t GLASS COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF NEW J'EY.

Application filed November 1, 191a To all whom it may concern:

Be it known that I, FRANK C. ASHE, a citizen of the United States, residing at State of Pennsylvana, have invented certain new and useful Improvements in Headlight Lenses, of which the following is a specification.

This invention relates to improvements in headlights for automobiles, and the like, and more particularly to a lens or cover glass employed in lights of the character mentioned.

The prime object of the present invention is to provide a lens or cover glass having the required qualities to eliminate the objectionable glare and, at the same time, of such a construction that the desired illuminating qualities of the headlight, such for example, as the sidewise distribution of light rays, and the illumination of the road a suflicient distance in front of the machine, is maintained.

In the accompanying drawings which illustrate. an application of my invention,

Fig. 1 is a rear elevational view of a lens or cover glass embodying my invention;

Fig. 2, a central vertical sectional view taken on the line 2-2 of Fig. 1;

Fig. 3, a vertical sectional view, the section being taken on line 3-3 of Fig. 1;

Figs. 4 and 5, horizontal sections respectively taken on lines 4-4= and 5-5 of Fig. 1;

Fi 6, a diagrammatic view particularly showing the lens divided into a plurality of areas from the standpoint of spread of the beam;

Fig. 7, detail views of prisms disposed in a specified area or areas; and

Fig. 8, similar views of prisms disposed in other areas of the lens or cover glass.

Referring to the drawings, and as preferr ed, my improved lens or cover glass in-- eludes two sets of combined downwardly deflecting and horizontally deflecting triangularly faced prisms 2 and 3, the base lines of the prisms of each set making an angle with the horizontal axis (see line 4-4: of

Fig. 1) and the verticalv axis of the lens or cover glass (see line 2-2 of Fig. 1), the

base lines of the two sets being tilted an equal amount on opposite sides of the vertical. The two sets 2 and 3 are mutually intersecting and result in the formation of a Y multiplicity of prisms with triangular faces HEADLIGHT tans.

Serial No. 335,621.

acting to deflect the light rays downwardly and alternately to the right and left of the axis of the beam of light. By this arrangement contiguous diagonally extending rows 9i alternately arranged orinclined prisms are provided, the prisms being so arranged as to give lateral deflection in opposite directlons.

As shown, the lines 4:, 4:, designate the traces of the bases of the set of prisms 2 and the lines 5, 5, the traces of the bases of set 3.

Lines 6, 6, designate the division lines between the triangular prisms.

It will be understood that the relative downward and lateral deflection may be determined by the angle that the bases of the prisms make with the horizontal and that the magnitude of the deflection is determined by the retracting angles of the prisms.

7 designates risms having horizontal base lines, and whie T prefer'to employ these last mentioned prisms, they may be omitted and the areas occupied by said prisms may be formed of plane glass or of the triangular prisms.

In order to produce the desired efficient lens or cover glass, meeting the requirements now so generally imposed as to the use of automobile headlights, the refractive power of the prisms employed, their configuration and arrangement must be carefully worked out, at the same time the cost of manufacture must be kept in mind. In the present embodiment of my invention, I provide triangular prisms of different refractive powers and arrange said prisms in different groups or in difl'erent areas, the triangular prisms being employed either when portions provided with the prisms 7 having the horizontal base are employed or with plane glass.

In the diagrammatic view (Fig. 6), T have shown the lens or cover glass divided into different areas. These areas, from the standpoint of spread of the beam from a reflector of the headlight to which my cover glass is designed to be attached, should'preferably be five in number. Thus, the areas designated a, a, represent the portions of the cover .glass where the vertical spread is the greatest. The areas I), b, are the portlons where-the vertical spread is small and the horizontal spread is the greatest. The area marked 0 represents the portion where the vertical and horizontal spread are approximately e ual.

The dlfi'erence in deflection required in these different areas is provided in the following manner. The area a is covered by the triangular prisms, described above,- dc signed to give the proper downward and sidewise deflection. The areas a, a, are covered with prisms. of the same kind but with a greater refracting angle, which eliminates the upward spread and at the same time produces the increase in the lateral spread which in this region is normally small. The areas I), b, are covered with prisms having horizontal bases, and designed to produce only a slight deflection downward, as the horizontal spread on this area is already considerable and the vertical spread is small.

Dividing the lens or cover glass with relation to thespread of the beam from a reflector into a plurality of areas having different characteristic features designed to produce the desired downward and horizontal deflections, constitutes an important and characteristic feature of my invention.

The prisms disposed in areas a, a are particularly shown by Fig. 7 and the, prisms of portions 0, c by Fig. 8.

What I claim is:

1. A headlight lens having a portion of its face provided with a plurality of contiguous triangularl faced prisms which are thickest at them base, each prism being formed with its base line at an angle to the horizontal and vertical axes of the lens and having its three sides common to contiguous prisms.

2. A headlight lens having two sets of triangularly faced'prisms on its face, each prism having a single base which is at an angle to the horizontal and vertical axes of the lens, with adjacent prisms of each set arranged to deflect the rays of light laterally in opposite directions and downwardly, the prisms bein arranged in contiguous diagonally exten ing rows, the bases of opposed sets being in intersecting diagonal lljines, and the PI'ISIIIS} being thickest at their ases.

3. A headlight lens having one face divided into a plurality of areas and having the areas covered with adjacent triangularly faced prisms, the inclination of each of the faces being opposite to that of the next adacent faces, the, refractive angles of the Laaaot? one side, which forms the base thereof, some of the prisms being reversed to the others, the bases of the prisms extending in intersecting diagonal lines across the lens, the prisms in different areas having different characteristics for lateral and horizontal deflection.

5. A headlight lens divided relatively to the spread of a beam of light through a reflector into a plurality of areas, said areas including groups of relatively small prisms arranged to give vertical and lateral deflec tion, the prisms of one group having different vertical and lateral deflecting charac teristics from those of another group, one group having relatively even vertical and lateral deflecting properties being disposed over the portions of the lens where a beam .of light passing therethrough has both a vertical and a lateral spread in substantially equal proportions, and other groups in which the prisms have reater properties for downward deflection heing disposed in that part of the lens where the rays having a relatively reat vertical spread and a relatively small htteral spread pass. a

6. A headlight lens having a portion of its face provided with diagonally extending rows of alternately inclined triangular shaped prism faces arranged to give lateral deflection of light in opposite directions,

each prism being thickest along one sidethereof which forms its base, all of said prism faces being inclined from the'vertical 1n the same direction to ive horizontal deflection, the degree ofinclination of the faces in difi'erent areas being different to vary the lateral and horizontal deflection at different points.

In testimon whereof I aflix my signature in presence 0 two witnesses.

I FRANK C. ASHE.

Witnesses:

J. M. GEocHncAN, Lois WINJEMAN. 

